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#1
Posted to rec.woodworking
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Need more power?
I've been using a Jet 16" Bandsaw for about 5 years. I've always
had to take it slow with this saw while resawing. It would pop circuits and bog down. I rewired it for 220 and that made a big difference, but I still had to take it slow. My current project requires me to build some bifold doors. The rails and styls are 2x6 Douglas fur. I need to bring the board thickness down to 1 1/16" and rather than run them through my plainer a bunch of times I am resawing them. About halfway through the stack things went wrong. I hit a piece of wood that was not completely dry. My blade was starting to get dull by this time as well. Rather than stopping and sharpening the blade and going to a dry piece of lumber, I forced it and ended up burning out the capacitors on my motor. (No need to kick a man when he's down here fellas, I know what I did wrong.) I've replaced the capacitors and the saw still has no power. I've come to the conclusion that some of the windings in the motor have broken from being overheated and the motor is toast. I've researched the various motors from Jet. There are three that will fit the saw without having to fabricate a mounting. · The original 1.5 hp replacement at $230 · The standard 1.75 hp off Jet's 18" model at $451 · Or my favorite the 3hp option for their 18" Bandsaw at $533 I'm concerned about going back to a 1.5 hp because it always seemed under powered before. If I were to spend the money for a larger motor, I feel that I might as well go for the big Kahuna. This brings me to my questions. 1. Is there such a thing as too much power? 2. Could I cause more problems than I solve? 3. Is the 1.5 horse really enough power and I just suck at setup and that's why I had the problems to beguine with? I appreciate any and all responses. ~Craig |
#2
Posted to rec.woodworking
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Need more power?
Do they show a 3-phase motor option for 3-5hp? If so, it should be less
expensive and have more power. Get a single phase input VFD and have variable speed as well. Various other options come to mind but would not be a factory configured option. Respectfully, Ron Moore "RCStrunk" wrote in message oups.com... I've been using a Jet 16" Bandsaw for about 5 years. I've always had to take it slow with this saw while resawing. It would pop circuits and bog down. I rewired it for 220 and that made a big difference, but I still had to take it slow. My current project requires me to build some bifold doors. The rails and styls are 2x6 Douglas fur. I need to bring the board thickness down to 1 1/16" and rather than run them through my plainer a bunch of times I am resawing them. About halfway through the stack things went wrong. I hit a piece of wood that was not completely dry. My blade was starting to get dull by this time as well. Rather than stopping and sharpening the blade and going to a dry piece of lumber, I forced it and ended up burning out the capacitors on my motor. (No need to kick a man when he's down here fellas, I know what I did wrong.) I've replaced the capacitors and the saw still has no power. I've come to the conclusion that some of the windings in the motor have broken from being overheated and the motor is toast. I've researched the various motors from Jet. There are three that will fit the saw without having to fabricate a mounting. · The original 1.5 hp replacement at $230 · The standard 1.75 hp off Jet's 18" model at $451 · Or my favorite the 3hp option for their 18" Bandsaw at $533 I'm concerned about going back to a 1.5 hp because it always seemed under powered before. If I were to spend the money for a larger motor, I feel that I might as well go for the big Kahuna. This brings me to my questions. 1. Is there such a thing as too much power? 2. Could I cause more problems than I solve? 3. Is the 1.5 horse really enough power and I just suck at setup and that's why I had the problems to beguine with? I appreciate any and all responses. ~Craig |
#3
Posted to rec.woodworking
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Need more power?
1. Yes.
2. Yes. If the blade bogs down and the motor forces things then you may end up breaking or bending the wheels, pulleys, or frame. 3. 1.5HP should be enough. Are you using the right blade? A blade with too many teeth will load up with sawdust and bind in the kerf. For resawing I use a sharp 3TPI blade and have no trouble resawing 6" hard maple with only 1HP. Art "RCStrunk" wrote in message oups.com... [snip] 1. Is there such a thing as too much power? 2. Could I cause more problems than I solve? 3. Is the 1.5 horse really enough power and I just suck at setup and that's why I had the problems to beguine with? I appreciate any and all responses. ~Craig |
#4
Posted to rec.woodworking
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Need more power?
"RCStrunk" wrote in message oups.com... I've been using a Jet 16" Bandsaw for about 5 years. I've always had to take it slow with this saw while resawing. It would pop circuits and bog down. I rewired it for 220 and that made a big difference, but I still had to take it slow. My current project requires me to build some bifold doors. The rails and styls are 2x6 Douglas fur. I need to bring the board thickness down to 1 1/16" and rather than run them through my plainer a bunch of times I am resawing them. About halfway through the stack things went wrong. I hit a piece of wood that was not completely dry. My blade was starting to get dull by this time as well. Rather than stopping and sharpening the blade and going to a dry piece of lumber, I forced it and ended up burning out the capacitors on my motor. (No need to kick a man when he's down here fellas, I know what I did wrong.) I've replaced the capacitors and the saw still has no power. I've come to the conclusion that some of the windings in the motor have broken from being overheated and the motor is toast. I've researched the various motors from Jet. There are three that will fit the saw without having to fabricate a mounting. · The original 1.5 hp replacement at $230 · The standard 1.75 hp off Jet's 18" model at $451 · Or my favorite the 3hp option for their 18" Bandsaw at $533 I'm concerned about going back to a 1.5 hp because it always seemed under powered before. If I were to spend the money for a larger motor, I feel that I might as well go for the big Kahuna. This brings me to my questions. 1. Is there such a thing as too much power? 2. Could I cause more problems than I solve? 3. Is the 1.5 horse really enough power and I just suck at setup and that's why I had the problems to beguine with? I appreciate any and all responses. ~Craig I have the same saw. It too is wired for 220 and so-far I'm able to re-saw any wood I stuff in it. I do use a 3tpi 3/4" Lenox blade. Is only bogs down when the blade gets dull. Replace the motor, get a good blade. Dave |
#5
Posted to rec.woodworking
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Need more power?
Thank you everyone for all your responses. I've been using 3 TPI
¾" blades I've purchased from various internet venders. I'll take your advice and replace the motor with the original 1.5hp and get a Lenox blade. Happy crafting... Teamcasa wrote: I have the same saw. It too is wired for 220 and so-far I'm able to re-saw any wood I stuff in it. I do use a 3tpi 3/4" Lenox blade. Is only bogs down when the blade gets dull. Replace the motor, get a good blade. Dave |
#6
Posted to rec.woodworking
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Need more power?
On 29 Oct 2006 15:38:01 -0800, "RCStrunk"
wrote: .... 1. Is there such a thing as too much power? 2. Could I cause more problems than I solve? 3. Is the 1.5 horse really enough power and I just suck at setup and that's why I had the problems to beguine with? .... 1. Yes, of course. But is upgrading to a 3HP motor too much power for the saw? Let's look at some back of the envelope calculations here. You've got a 16" bandsaw. That means the vertical force pulling the blade through the workpiece is the torque applied by the motor to the lower wheel divided by the radius of the wheel. _All_ of that force is resisted by the table and its supporting structure. None of it is seen by the upper wheel or the structure supporting the upper wheel. So, for a worst case analysis, assume 100% efficiency in transmitting motor torque to a vertical load on the saw's table. F = 12*T/R Whe F = vertical load on the saw table (Pounds) T = Torque developed by the motor (Foot-Pounds) R = Radius of the saw's driven (lower) wheel (inches) 12 = Conversion factor from inches to feet Since the radius of the driven wheel is constant, the maximum load on the saw's table will occur when the motor develops it's maximum torque. This will be the "Locked Rotor Torque" of the motor and will occur if/when blade binds in the workpiece and stalls the motor. So what is the locked rotor torque of the motors you are considering. Since I don't know the specific motor, I looked at a typical 3HP 1725 RPM, 230v motor. (Baldor Model L3705) (Ref: http://www.baldor.com ) which has a locked rotor torque of 45 Foot-Pounds. Plugging in those numbers: F = 12*45/8 = 67.5 Pounds. I have a Jet 16" bandsaw. I don't believe 70 pounds applied vertically to the table would have any detrimental effects on the structure of that saw. Nor do I believe 45 Foot-Pounds torque applied to the lower wheel would have any adverse effects. The 70 pound load would be reacted by the lower wheel mount and bearings. That would be my only point of concern, but without any specific information about those bearings, I would guess that additional load is within their capability. Note that the additional load of the 3HP is only 45 pounds more than that developed by a 1.5HP motor under the same circumstances (Ref: Baldor Model L3514M) Only you can determine whether the $500+ cost of the 3HP motor is cost effective for you. But if you are worried about overloading the saw's components, I can only say that, except for the cost, I wouldn't hesitate to install a 3HP motor on my 16" bandsaw. |
#7
Posted to rec.woodworking
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Need more power?
Tom wrote: Only you can determine whether the $500+ cost of the 3HP motor is cost effective for you. But if you are worried about overloading the saw's components, I can only say that, except for the cost, I wouldn't hesitate to install a 3HP motor on my 16" bandsaw. Yes Tom, the $500 question is the one posed by my loving wife as well. Is it worth it? I think I'm going to stick with my last post and get the 1.5hp. If I lose another motor after changing blade manufacturers, then I'll move to the 3hp motor. Thanks for your response... |
#8
Posted to rec.woodworking
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Need more power?
"RCStrunk" wrote in news:1162178800.606469.76930
@i42g2000cwa.googlegroups.com: Tom wrote: Only you can determine whether the $500+ cost of the 3HP motor is cost effective for you. But if you are worried about overloading the saw's components, I can only say that, except for the cost, I wouldn't hesitate to install a 3HP motor on my 16" bandsaw. Yes Tom, the $500 question is the one posed by my loving wife as well. Is it worth it? I think I'm going to stick with my last post and get the 1.5hp. If I lose another motor after changing blade manufacturers, then I'll move to the 3hp motor. Thanks for your response... If you lose another motor on that saw, I wouldn't buy another motor, but rather another saw. Preferably from Laguna or MiniMax. But that's a pretty strong saw you have there now. Patriarch |
#9
Posted to rec.woodworking
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Need more power?
In article , Tom Veatch wrote:
On 29 Oct 2006 15:38:01 -0800, "RCStrunk" wrote: ... 1. Is there such a thing as too much power? 2. Could I cause more problems than I solve? 3. Is the 1.5 horse really enough power and I just suck at setup and that's why I had the problems to beguine with? ... 1. Yes, of course. But is upgrading to a 3HP motor too much power for the saw? Let's look at some back of the envelope calculations here. You've got a 16" bandsaw. That means the vertical force pulling the blade through the workpiece is the torque applied by the motor to the lower wheel divided by the radius of the wheel. _All_ of that force is resisted by the table and its supporting structure. None of it is seen by the upper wheel or the structure supporting the upper wheel. So, for a worst case analysis, assume 100% efficiency in transmitting motor torque to a vertical load on the saw's table. F = 12*T/R Whe F = vertical load on the saw table (Pounds) T = Torque developed by the motor (Foot-Pounds) R = Radius of the saw's driven (lower) wheel (inches) 12 = Conversion factor from inches to feet Since the radius of the driven wheel is constant, the maximum load on the saw's table will occur when the motor develops it's maximum torque. This will be the "Locked Rotor Torque" of the motor and will occur if/when blade binds in the workpiece and stalls the motor. So what is the locked rotor torque of the motors you are considering. Since I don't know the specific motor, I looked at a typical 3HP 1725 RPM, 230v motor. (Baldor Model L3705) (Ref: http://www.baldor.com ) which has a locked rotor torque of 45 Foot-Pounds. Plugging in those numbers: F = 12*45/8 = 67.5 Pounds. I have a Jet 16" bandsaw. I don't believe 70 pounds applied vertically to the table would have any detrimental effects on the structure of that saw. Nor do I believe 45 Foot-Pounds torque applied to the lower wheel would have any adverse effects. The 70 pound load would be reacted by the lower wheel mount and bearings. That would be my only point of concern, but without any specific information about those bearings, I would guess that additional load is within their capability. Note that the additional load of the 3HP is only 45 pounds more than that developed by a 1.5HP motor under the same circumstances (Ref: Baldor Model L3514M) Only you can determine whether the $500+ cost of the 3HP motor is cost effective for you. But if you are worried about overloading the saw's components, I can only say that, except for the cost, I wouldn't hesitate to install a 3HP motor on my 16" bandsaw. There are a few problems with this analysis: 1. An induction motor does not necessarily develop it's maximum torque at locked rotor, it is not at all uncommon for the maximum torque to be developed near the rated speed of the motor. 2. The torque applied to the lower wheel, and subsequently to the table & supports as you posit, will be multiplied in inverse proportion to the degree that the gearing, pulleys, etc. reduce the speed of the lower wheel. 3. Intuition he Assume that 70 lbs downward force exerted through the blade is correct. I can easily grab hold of a seventy pound weight and lift it with one hand (OK, maybe not as easily as I could have 30 years ago.) I really doubt that I could grab hold of a 16" bandsaw blade, turn the saw on, and keep the blade from moving! Not to say that the saw in question would not benefit from the 3 HP motor or necessarily be damaged by it; I would suggest looking at similar saws and seeing what size motors they use, or (dare I suggest it) calleing JET and asking them. -- For every complicated, difficult problem, there is a simple, easy solution that does not work. Larry Wasserman - Baltimore Maryland - |
#11
Posted to rec.woodworking
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Need more power?
Tom wrote: Power(P) = Torque(T) * Rotational Velocity(V) Or T(ftlb) = P(ftlb/sec) / V(radians/sec) But V(radians/sec) = V(RPM) * 2pi (radians/rev) / 60 (sec/min) where RPM is revolutions per minute Or V(radians/sec) = 0.1047*V(RPM) And Power(P) = P(HP) * (550 ftlb/sec) So T(ftlb) = 550 * P(HP) / 0.1047 * V(RPM) Or T = 5253 * P/V Where T = torque developed by the motor expressed in foot pounds P = power developed by the motor expressed in Horsepower V = speed of the motor expressed in revolutions per minute For the motor referenced: P = 3 HP V = 1725 RPM Or T = 5253 * 3 / 1725 = 9.136 Draw your own conclusions. Wow, I had no idea this post would get so many responses. Thanks for the lesson in calculating torque. Get calls from NASA much? ~Craig |
#12
Posted to rec.woodworking
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Need more power?
On 30 Oct 2006 13:00:56 -0800, "RCStrunk"
wrote: Get calls from NASA much? Did some work for them at MSFC Huntsville back in the early '70s on the Space Shuttle Main Engine (SSME) Controller and Saturn V Launch Profile. Got tired and disgusted with the bureaucracy and left to do non-government stuff.. |
#13
Posted to rec.woodworking
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Need more power?
In article , Tom Veatch wrote:
...snipped... 3. Intuition he Assume that 70 lbs downward force exerted through the blade is correct. I can easily grab hold of a seventy pound weight and lift it with one hand (OK, maybe not as easily as I could have 30 years ago.) I really doubt that I could grab hold of a 16" bandsaw blade, turn the saw on, and keep the blade from moving! As you say, that lift would have been much easier 30-40 years ago, but I also could do it - if I can get a good grip on it. However, attach that 70 pounds to the end of a 1/2 to 3/4 by .035 strip of steel. Can you pinch that strip between your thumb and finger like you would a bandsaw blade and lift the 70 lbs? If you can, you probably one of those people who crack pecans using just your thumb and forefinger. I know I can't - except maybe the "papershell" variety. Well, of course I would use a vise grips pliers if I was inclined to actually attempt this. But since you mention it, 30 years ago, I could crack a pecan by hand. -- For every complicated, difficult problem, there is a simple, easy solution that does not work. Larry Wasserman - Baltimore Maryland - |
#15
Posted to rec.woodworking
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Need more power?
On 29 Oct 2006 15:38:01 -0800, "RCStrunk"
wrote: I've researched the various motors from Jet. There are three that will fit the saw without having to fabricate a mounting. · The original 1.5 hp replacement at $230 · The standard 1.75 hp off Jet's 18" model at $451 · Or my favorite the 3hp option for their 18" Bandsaw at $533 Ack! Is it not a standard NEMA mount? Grizzly's motors are about half those figures. I'm sure they're spiffy motors and all, but you've already fried one of them already... -Leuf |
#16
Posted to rec.woodworking
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Need more power?
On Sun, 29 Oct 2006 23:40:02 -0500, Leuf
wrote: On 29 Oct 2006 15:38:01 -0800, "RCStrunk" wrote: Ack! Is it not a standard NEMA mount? .... I certainly stand to be corrected, but I don't believe they are. At one time I was considering installing a larger motor on my 16" Jet and took some measurements off the mount (face mounted). Since I didn't remove the motor or the lower wheel, my measurements were far from being precise. Couldn't find any NEMA configuration that looked close enough. There was an IEC (Metric) configuration that was closer but due to the (im)precision of my measurements, I can't say with any certainty that the motor was/is an IEC mount. (couldn't find anything on the motor nameplate that said one way or the other.) |
#17
Posted to rec.woodworking
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Need more power?
Leuf wrote: On 29 Oct 2006 15:38:01 -0800, "RCStrunk" wrote: I've researched the various motors from Jet. There are three that will fit the saw without having to fabricate a mounting. · The original 1.5 hp replacement at $230 · The standard 1.75 hp off Jet's 18" model at $451 · Or my favorite the 3hp option for their 18" Bandsaw at $533 Ack! Is it not a standard NEMA mount? Grizzly's motors are about half those figures. I'm sure they're spiffy motors and all, but you've already fried one of them already... -Leuf You're correct Leuf, Jet uses a proprietary mounting not a standard NEMA face. When I burned out the motor the first place I looked was Granger. I thought I could fab a new mount but decided I didn't want the extra challenge. To make matters worse the bolt holes are in a diamond pattern not square. I don't know why Jet made the decision not to use a standard mount. I guess they want my return business... ~Craig |
#18
Posted to rec.woodworking
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Need more power?
I have the older 18" model and thought it was underpowered with 1 1/2 hp at
first. However, after reading Duginske's "Bandsaw Handbook" and giving the (still fairly new then) saw a good tune up and selecting the right blades, it can resaw just about anything I throw at it. 2x6 fir would be no trouble whatsoever. 10" Oak goes pretty easily. 10" Jatoba slows her down a good bit. 1 1/2hp is adequate for 90% of the things I do with it, the1.75hp would probably make it real close to 100% . However, for the price, it'd seem that the 3 hp is not a far cry from the 1.75, and both are substantially more than the 1.5. I really don't forsee any problems going with the 3hp. Let us know what you decide and how it works! --dave "RCStrunk" wrote in message oups.com... I've been using a Jet 16" Bandsaw for about 5 years. I've always had to take it slow with this saw while resawing. It would pop circuits and bog down. I rewired it for 220 and that made a big difference, but I still had to take it slow. My current project requires me to build some bifold doors. The rails and styls are 2x6 Douglas fur. I need to bring the board thickness down to 1 1/16" and rather than run them through my plainer a bunch of times I am resawing them. About halfway through the stack things went wrong. I hit a piece of wood that was not completely dry. My blade was starting to get dull by this time as well. Rather than stopping and sharpening the blade and going to a dry piece of lumber, I forced it and ended up burning out the capacitors on my motor. (No need to kick a man when he's down here fellas, I know what I did wrong.) I've replaced the capacitors and the saw still has no power. I've come to the conclusion that some of the windings in the motor have broken from being overheated and the motor is toast. I've researched the various motors from Jet. There are three that will fit the saw without having to fabricate a mounting. · The original 1.5 hp replacement at $230 · The standard 1.75 hp off Jet's 18" model at $451 · Or my favorite the 3hp option for their 18" Bandsaw at $533 I'm concerned about going back to a 1.5 hp because it always seemed under powered before. If I were to spend the money for a larger motor, I feel that I might as well go for the big Kahuna. This brings me to my questions. 1. Is there such a thing as too much power? 2. Could I cause more problems than I solve? 3. Is the 1.5 horse really enough power and I just suck at setup and that's why I had the problems to beguine with? I appreciate any and all responses. ~Craig |
#19
Posted to rec.woodworking
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Need more power?
my 18" bandsaw has a 2hp motor and it seems to have adequate power for my uses. I don't resaw a lot though, so YMMV. the pulleys and belts on your saw were engineered for 1.5hp. if you exceed that by too much what is likely to happen is that the belt will slip when you load it up- the motor won't bog down, but the power won't be transmitted to the blade and you'll be cooking belts if you do it a lot. in other words, the extra power will be wasted. you _could_ upgrade to a triple groove sheave and be able to use a 3hp motor on it, but make sure the bearings are rated for it and that the frame is stiff enough to be able to tension that properly. |
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